BLD/Roofing/TBT-BLD-013

Basement Waterproofing Safety

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Basement Waterproofing Safety

Toolbox Talk Record

Ref: TBT-BLD-013  |  Issue: 1  |  Date: March 2026
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What?

  • Basement waterproofing prevents water ingress through below-ground walls and floor slabs.
  • Common systems include tanking membranes, cavity drain systems, and cementitious coatings.
  • Many waterproofing products contain solvents, resins, or bitumen that create harmful fumes.
  • Enclosed basement areas with poor ventilation can quickly accumulate hazardous vapour concentrations.
  • COSHH assessments are required for all waterproofing products before application begins.
  • Torch-applied membranes involve hot works and create fire risks in confined basement spaces.
  • Primer coats are often highly flammable and must be applied with adequate forced ventilation.
  • Working in basements combines below-ground risks including flooding, poor access, and low headroom.
  • Correct surface preparation may generate silica dust requiring RPE and extraction equipment.
  • Waterproofing often takes place before permanent ventilation and lighting are installed.

Why?

Fume exposureSolvent and bitumen fumes accumulate quickly in enclosed basements and can cause loss of consciousness or long-term illness.
Fire riskFlammable primers and torch-on membranes in a confined basement create a serious fire and explosion hazard.
Health protectionSkin contact with resins and bitumen causes dermatitis, while dust from preparation contains respirable silica.
Do Don't
  • Complete a COSHH assessment for every waterproofing product used on site
  • Provide forced mechanical ventilation throughout the application process
  • Monitor the atmosphere for solvent vapour and oxygen levels during work
  • Obtain a hot works permit before using torch-applied membrane systems
  • Wear RPE, chemical-resistant gloves, and appropriate skin protection
  • Ensure fire extinguishers are immediately available during hot works
  • Plan escape routes and brief workers on emergency procedures below ground
  • Provide temporary lighting that meets standards for the working environment
  • Allow adequate flash-off time for primers before applying membranes
  • Restrict access to the basement during application to essential workers only
  • DON'T apply solvent-based products in basements without forced ventilation
  • DON'T use open flames near flammable primers or solvent-based coatings
  • DON'T ignore product safety data sheets — follow them without exception
  • DON'T allow smoking, naked flames, or sparks in the application area
  • DON'T work in a basement alone during waterproofing operations
  • DON'T skip atmospheric monitoring because the area feels well ventilated
  • DON'T store excess flammable materials in the basement work area
  • DON'T remove RPE during application or while fumes are still present
  • DON'T enter the basement without confirming temporary lighting is working
  • DON'T ignore headaches, dizziness, or nausea — leave the area immediately

See also: COSHH Awareness | Hot Works Fire Prevention
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